


When Things Get Heated

by Shelamnia



Category: Big Hero 6 (2014)
Genre: Alpha/Beta/Omega Dynamics, Humor, M/M, Mating Cycles/In Heat, Sappy, Unexpected Results, alpha!Tadashi, omega!Hiro
Language: English
Status: In-Progress
Published: 2015-05-20
Updated: 2015-05-20
Packaged: 2018-03-31 12:23:48
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 8,068
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3977896
Author URL: https://archiveofourown.org/users/Shelamnia/pseuds/Shelamnia
Summary: <blockquote class="userstuff">
              <p>Hiro is sick of heat suppressants, but he can't go through his heat alone safely. He decides to ask Tadashi - his alpha brother - to help him through his heat so that it'll be short, if unpleasant. </p><p>It doesn't quite go as planned.</p>
            </blockquote>





	When Things Get Heated

**Author's Note:**

> **Modeled after[Eat, Knot, Love (Teen Wolf)](http://archiveofourown.org/works/926909/chapters/1802031) by pandabomb. ** Same style, and same kind of A/B/O universe with a few changes of my own. Of course, the original is better and you should go read it!! 
> 
> Also, Big Hero 6 isn't mine. 
> 
> Now that credit has been given where credit is due…

“Tadashi, please? I know it’s not unheard of.”

“Hiro, I’m not sure it’s what’s best for us.”

“Yea, well, you _know_ what the heat suppressants do to me – they’d make my heat last until well into fall quarter. Or you could just help me get through it in a few days.”

Tadashi put down the book he was reading next to him on his bed. Hiro was sitting at the foot of the bed, waiting for his brother to decline or accept.

With a sigh, Tadashi said, “There are other options.”

“Mm, like getting fucked by a total stranger for a few days.”

“Language.”

“Okay, sharing my first unsuppressed heat with a total stranger. Same thing. It’s not like anything could go wrong, like they turn out to be an asshole and mate compatible and I’m basically fucked and stuck.”

Tadashi sighed, looking at Hiro apprehensively. “ _Language_. Have you tried talking to our friends?”

“Yea, turns out they’re not alphas or not available. Like, taken.”

Dragging a hand down his face, Tadashi closed his eyes. “I’m your _brother_.”

“Exactly,” Hiro retorted. “Omega heats are shorter when the alpha isn’t mate material.”

“And it’s generally unpleasant for the alpha, and the omega generally feels less satisfied and depressed during and after, don’t forget that.”

Hiro shrugged. “It’s better than wet underwear and poor appetite and being miserable for over a month.”

“You don’t know that.”

Hiro sighed and flopped back on the bed, just beyond Tadashi’s feet. “Look, can you give me a yes or a no? Will you help me through my heat or not?”

Hiro watched as a number of emotions flitted across his brother’s face. He could tell that Tadashi was seriously considering it, just because Hiro asked for it.

Privately, Hiro thought that Tadashi was the best thing that could have ever happened to Hiro. Protective, caring, gentle… just all around wonderful. But they were brothers and they could never be any closer than that.

Tadashi sighed. “Why don’t we talk to Aunt Cass?”

It wasn’t a question.

BH6BH6BH6

_Hiro feels even hotter as Tadashi’s fingers prep him, thrusting all the while and trying to get deeper._

_His other hand slides over the hot skin of Hiro’s soft stomach, around his sides and up to his chest. Hiro covers the hand with his own, trying to get Tadashi to hurry up._

_“Please,” Hiro says. Tadashi looks at him, in the eyes, and pauses._

_That’s even worse for Hiro. He thrusts up. His thighs are on Tadashi’s, so he could sit up in his lap if he wanted. But right now, his hole is begging for fingering and fucking. Slick dribbles out as Tadashi resumes his thrusts._

_“I’m ready,” Hiro tries. “Come on!”_

_Tadashi shakes his head, but doesn’t stop this time. “I want you to come first. It’ll help me get into it, remember?”_

_Hiro keens, frustrated by Tadashi’s logic. At least Tadashi is good with his hands._

_Hiro can feel another finger slip into his hole and prod at his insides. The fingers slip in and out, filling and emptying him with each cycle._

_Tadashi’s free hand slips down Hiro’s front until it reaches his waist, holding him down. With a whimper, Hiro wriggles, trying to get some friction._

_Hiro gasps as Tadashi’s fingers brush against his prostate. It’s nothing like Hiro’s own fingers, and nothing like some of the toys he’s tried._

_“Here, huh?”_

_The fingers change their movements to very short, sharp thrusts aimed directly at Hiro’s prostate. The younger gasps, his hole momentarily clenching as the new movements focus the pleasure deep inside him._

_Hiro feels like he’s high, soaring like a kite. Tadashi makes him feel so good – not just physically, either. Tadashi is safe. He’s trust and love. He’s everything to Hiro, and now he’s pleasuring him, too._

BH6BH6BH6

Aunt Cass was open-minded and thoughtful. For that, Hiro was extremely grateful. Not all guardians would react well if their younger omega charge asked about getting fucked by the older alpha charge.

“Um… well.” Being a beta, Aunt Cass wouldn’t exactly have experience with the whole alpha-and-omega mating-heat thing. Hiro wasn’t exactly experienced with it either, but he’d experienced the suppress-natural-instincts-and-be-fucking-miserable thing. He knew he didn’t want to do that.

“I mean, I’ve heard about those omega clinics,” Aunt Cass said hesitantly. She looked so out of her depth, Hiro almost felt bad for her.

“And how sometimes things go very, very wrong?” Hiro asked sweetly.

Tadashi nudged him. “Hiro.”

Hiro rolled his eyes and looked away.

Aunt Cass thought. And thought and thought.

Hiro started tapping his foot.

“All right, I guess I’m okay with it – but _only_ if _both_ of you do your research and play with all the cards on the table, and everything is completely consensual. And you have to talk to a doctor. Neither of you should be afraid to back out at any point.”

Hiro grinned. That is _exactly_ what he’d been hoping for. “Okay! I’ve looked up a number of contraceptive options and pheromone reduction drugs and – ”

Tadashi stopped him with a nudge. “ _Both_ of us, Hiro. We’ll have to look at this together.”

Aunt Cass nodded approvingly. “All right, then.”

BH6BH6BH6

_Hiro pants, his eyes half-lidded as he comes down from his orgasm. He’s shaking a little, but that’s okay – Tadashi is right there, a hand holding him steady on his belly._

_Tadashi is looking at his hand, the one that was inside Hiro. It’s shiny with slick, and Hiro smiles a little._

_“Lick it,” he says._

_Tadashi blinks, realizing Hiro was watching him examine it. He lowers his hand a bit._

_“Lick it,” Hiro says again. He doesn’t know why exactly, but he knows Tadashi should taste him._

_Tadashi is silent for a moment, and then complies. His pink tongue slips between his lips and barely touches his hand, just sampling the flavor._

_Hiro watches as Tadashi’s eyes widen and darken – his pupil blow wide as he opens his mouth and presses the flat of his tongue against his fingers, licking more thoroughly and cleaning his hand off._

_Hiro half-huffs, half-laughs. The sight is turning him on again, and he can feel himself harden at the sight._

_Tadashi finishes licking off his hand, and he looks back at Hiro. “You taste so good,” he says, like he can’t believe he likes Hiro’s slick._

_Hiro giggles at the compliment. He makes to sit up, pushing himself up off his back with his arms._

_Little does Hiro know, he’s unleashed something in Tadashi. The elder lets him sit up in his lap for a second. Their lips meet, and Hiro can faintly taste something savory but sweet._

_When he pulls back, he looks into Tadashi’s eyes and sees something he’s never seen there before – something raw and untamed, not gentle or friendly but fierce. Tadashi wants, and Hiro has never seen him like this before._

_Before Hiro can think more about Tadashi’s expression, he finds himself thrown back on the bed, his legs swinging up for a brief moment. Tadashi grabs his legs and twists, forcing Hiro to roll over._

_With a yelp, Hiro finds himself manhandled onto his front and much harder for it. His face mushes into the pillows as Tadashi’s hands move him around, spreading his thighs and balancing Hiro on his knees._

_Hiro feels Tadashi prod his entrance with something hard, and he draws in a shaky breath. His first time being fucked, and it’s by Tadashi._

_In that moment, Hiro thinks that he wouldn’t want it any other way._

_Tadashi slides in smoothly. Hiro’s muscles are practically opening him up, and slick is spilling out of him. The hot, rigid intrusion is large. It slips in deeper and deeper, slowly at first and then quicker once Tadashi seems to realize how loose Hiro is. Hiro gasps as Tadashi’s cock hits his prostate. He’s still sensitive from before, but he’s oh-so-ready for this._

_“Hiro,” Tadashi says, and Hiro can’t tell if it’s choked or pleasured._

_Hiro responds by tensing his ass as much as possible. Tadashi grunts, and his hips snap forward, pushing him deeper into Hiro. Hiro feels dizzy at the pleasurable push against that spot inside him._

_“You little…”_

_Tadashi seizes Hiro’s sides, more than hard enough to bruise. With a viciousness Hiro didn’t think was possible from Tadashi, the elder fucks him._

_Hiro pushes back a little to match him, but Tadashi’s grip on his hips does most of the work._

_A moan escapes Hiro’s lips, and Tadashi’s breathing picks up. Hiro feels slick running down his thighs, and sweat sticks the sheets to him. Pleasure is exploding inside him, and he can’t think. With every thrust, Tadashi drives into him deeper and deeper._

_If Hiro could think, he would remember that alpha precum has hormones to keep him from coming, and that alpha seed contains hormones that will extend both their orgasms when Tadashi knots._

_But instead, Hiro just basks in the overwhelming pleasure. Each thrust seems like it should make him come, but he just can’t. He keens as Tadashi leans forward more, hitting his prostate more steadily, and Hiro clenches mindlessly, already ready to come. The sounds Tadashi makes tells Hiro he’s close, but Hiro is too far gone to care._

_A few more sharp thrusts, and Hiro feels more fluids join his slick: hot seed coats his insides. Tadashi cries out as he releases into Hiro, and Hiro pushes back, desperate for the knot and for more stimulation._

_Hot seed scorches Hiro, and a second later, he’s spurting his own. The dick in him swells slowly, the pressure building as it widens at the base, locking all the seed inside him. Tadashi is still thrusting shallowly, breathing erratically._

_“Tada…” Hiro half-says in his orgasmic daze. His toes tingle and he feels like a limp noodle as endorphins rush through his system._

_“Hiro,” Tadashi whispers. He shifts, leaning to lie on top of Hiro from behind, and Hiro’s legs twitch as Tadashi pushes into his prostate again._

_Hiro’s so high on pleasure he’s not sure he’ll ever come down._

BH6BH6BH6

Wasabi looked over at Tadashi across their lunch, face blatantly shouting “WHAT THE FUCK” but mouth silent.

“Yea, I know. I can back out at any time, and so can he.”

Wasabi sputtered, trying to find something to say. He finally decided on, “That’s got to be, I don’t know, illegal or something! Hello? Incest?!”

Tadashi sighed. He’d worried about his friends reacting like this, so he decided to first talk to Wasabi and see what he thought, since out of all of them he was the least open-minded to this kind of thing. It was against the typical order of things, Tadashi supposed.

“I haven’t said I’ll go through with it yet. But the idea’s on the table, and wow, you should have seen Hiro a year and a half ago. He was completely miserable for well over a month. I can bring that down to a few days, four at most, and keep it from interfering with autumn classes.”

Wasabi frowned and considered this. “So you’d just, uh, _help_ him through his heat for a few days. You’ll both be miserable and awkward. And then it’d be over.”

“Yep. It happens sometimes, when siblings don’t get the same status.”

Wasabi considered. “You think it’s the best option, then?”

Tadashi shrugged. “I think the worst of it would be social repercussions,” he said honestly. He knew Wasabi would understand that he meant people in general, and it was by no means directed at him. “I mean, you know I can get people through heats.”

Wasabi frowned and looked at his sandwich, thinking. “You should get paid for that, really.”

Tadashi laughed. “Mm, well, I don’t like the idea of going through heats with total strangers just as much as Hiro doesn’t.”

Wasabi grinned. After a few beats of friendly silence, he asked, “So it’s his second heat?”

“Third.”

Wasabi looked surprised. “Wait, isn’t he sixteen now?”

Tadashi nodded. “Had his first when he was twelve, for a month under suppressants.”

“Wow. I mean, I can get him not wanting his heat suppressed, but wow. That’s… wow.”

“Yea.”

BH6BH6BH6

_“Hi, boys!” Aunt Cass’s voice echoes up the staircase. She seems quite lively. “It’s been four days – you all right up there? Is Hiro almost done? Tadashi, do you need something to eat?”_

_Hiro is half-asleep after a marathon of sex. He watches Tadashi get up out of bed and throw on a robe. Tadashi leans over, covers him with the sheets, and kisses him on the forehead._

_“I’ll be right back.”_

_That’s exactly the wrong thing to say to Hiro – possibly the last thing he wants to hear right now. “Tadashi!” Hiro cries, latching onto his arm, suddenly fully awake._

_Tadashi jumps but doesn’t say anything, letting Hiro hang off him like a naked leech. He clings to Tadashi – Tadashi can’t leave him, not when he’s awake, and he especially can’t leave him to do anything with another person. Hiro won’t allow it._

_“Tadashi?” Aunt Cass says, her voice much closer but her body still out of sight. “Are you both decent? I have some breakfast for you and some yogurt for Hiro.”_

_“One sec,” Tadashi answers, pulling the sheets around Hiro. “Yeah, we’re decent. But uh, I’m not sure you should come up.”_

_Hiro glares in the direction of the disembodied voice that Tadashi seems to know. But it doesn’t die because of his death glare. “Is everything all right?”_

_“Hiro’s temperature is still high,” Tadashi answers. “I think he’s still in heat.”_

_“You’re brothers – it shouldn’t last more than four days,” Aunt Cass says. “Is he sick?”_

_Tadashi takes one look at Hiro and says, “I don’t think so. I think he’s still in heat.”_

_Hiro holds on for dear life when the stranger’s head pops up from the staircase._

_The woman looks surprised. “That can’t be.”_

_Hiro grips Tadashi harder and openly growls at the threat to his alpha. If his alpha won’t do something about the stranger, he will._

_“Hiro!” Tadashi exclaims. “That’s Aunt Cass!”_

_The words “Aunt Cass” should ring all the bells in Hiro’s head, but everything is cottoned and muffled to Hiro, who isn’t thinking above a primal level._

_He growls as menacingly as he can._

_Aunt Cass looks alarmed, but she puts down the food and leaves, saying hesitantly, “Well, let me know when Hiro’s done…”_

BH6BH6BH6

They sat at the computer, Hiro in Tadashi’s lap, researching heats. Tadashi had his arms wrapped around Hiro’s waist as the younger one scrolled through the various articles they’d found.

Many of them suggested renting a place and getting laundry services. Almost all of them talked about recording the physical condition of the omega – how much they weighed, their temperature, water intake, et cetera and et cetera. Tadashi shifted beneath Hiro apprehensively.

“If we’re going through with this, then Baymax is going to watch us.”

“Uh, _what_?!” Hiro twisted around to face him.

Tadashi raised a finger, signaling for Hiro to shut up and listen. “Any other person watches, and you might attack them or they might be influenced by either of our pheromones. Baymax is built for caregiving, and I’d rather have help if we’re going to share your first unsuppressed heat. Baymax won’t emit any kind of pheromone, and you’re comfortable with him – or at least I think you are. He can keep records of your condition, in case anything happens.”

Hiro blinked, not sure what to say. “Um, are you into voyeurism?”

Tadashi sighed. “I don’t think so. But I’m not going through with this unless Baymax is there.”

Hiro ran a hand through his hair and looked down. “Fine. Baymax will be there. But only because you insist. And he has to be silent and act like he’s not there.”

Tadashi smiled. “All right then, I guess I’m in.”

BH6BH6BH6

_Hiro stirs. He’s being carried, but not by Tadashi, and he feels no real threat from whoever – or whatever – is holding him. It doesn’t smell like anything._

_“Hello, Hiro,” Baymax’s voice says, calm as ever._

_Hiro blinks slowly, dazed, and tired as fuck. “Tada…?” he slurs, confused by this scentless voice._

_“I am recording your weight.”_

_Hiro can’t seem to remember why Baymax is here, but he doesn’t really care. Right now, he just wants Tadashi, but he can’t seem to find the words.  His smell is everywhere, beckoning Hiro, reassuring him and making him want to cuddle until he wants to fuck again, but Tadashi himself isn’t there, and that’s a problem. “Tadashi…”_

_“Tadashi is showering.”_

_“I want,” Hiro says. Then he tries to get out of Baymax’s arms so he can get closer to Tadashi._

_But Hiro is not all there, and instead, he tumbles to the floor with a thud. Baymax moves to intervene as Hiro half-stands and practically staggers to the bathroom in search of Tadashi, but Hiro manages to avoid him. He fumbles with the doorknob until he gets it open, and breathes in the hot, warm air that smells strongly of his alpha._

_“Hiro?!” Tadashi says, pulling back the shower curtain to look upon hearing the door open. “Uh, I thought you’d be asleep for longer. I mean, I just knotted you.”_

_Hiro shakes his head slowly, suddenly feeling a bit more lucid. “You weren’t there.”_

_Tadashi seems to process this warily, nodding once. “Well, since you’re here, why don’t we shower together?”_

_Hiro doesn’t think about why Tadashi might not want him to shower alone for safety – he just clambers into the bathtub next to Tadashi, under the hot water._

_“I love you,” Hiro says suddenly, as Tadashi starts cleaning him gently with soap and water._

_Tadashi’s hands freeze for a moment before they keep going, running through Hiro’s hair and down his back. Soap makes his hands glide smoothly all over, and Hiro leans against Tadashi, completely uncaring of the fact that Tadashi was nearly clean and Hiro was far from it._

_“How long?” Hiro eventually asks, as Tadashi rubs soap down his legs._

_“Four and a half days.”_

_Hiro frowns, looking Tadashi in the eyes. He feels strangely coherent. “But… only twice.”_

_Tadashi doesn’t answer for a moment, instead reaching for the shower head so he can be sure to get all the soap off Hiro. “Twice what?”_

_“Knot.”_

_Tadashi blinks, before appearing to come to some kind of realization. Then he looks sad, and Hiro kisses his cheek, trying to make him smile. “Tadashi?”_

_The kiss only seems to make Tadashi blush, but he doesn’t look any happier – in fact, he looks kind of scared. Hiro cocks his head and hugs Tadashi, letting the warm water run over them. A moment later, Tadashi’s thick arms are around him, secure and pleasant._

_“It’s okay, Hiro. We’ll be okay.”_

_The water stops, and Hiro shivers, holding Tadashi closer. The air is cold and unpleasant. Hiro keens at the sensation._

_Tadashi shushes him, and a large, fluffy towel makes its way onto Hiro’s skin, patting gently and drawing away the moisture. Hiro whimpers when Tadashi turns him around to dry his front._

_“How are you feeling?” Tadashi asks._

_“Good,” Hiro replies, and it’s the truth. He’s clean and sated, and Tadashi is there, touching him._

_“Tired?” Tadashi asks._

_“Yea.”_

_Tadashi steps out of the shower and steadies Hiro as Hiro steps out. But Hiro is sleepy and off-kilter, and he falls over into Tadashi’s arms. Tadashi laughs a little as he props Hiro up again._

_Hiro doesn’t remember Tadashi carrying him back to their other, clean bed._

BH6BH6BH6

Hiro gaped as he watched Tadashi pull things off the shelf in the adult store.

“A dick-shaped water bottle?” Hiro asked, not sure if he should be amused, horrified, or just plain confused.

“Hey, you read article that with me,” Tadashi answered calmly. “You might be incoherent and unwilling to eat or drink. So I make it seem like you’re sucking on my – well, you know. And you stay hydrated.”

“It’s only for a few days. And I think I’d be able to tell your dick from a water bottle. Non-compatible heats mean the omega is more conscious, right?” Tadashi shrugged, and Hiro shook his head in disbelief. Tadashi was taking the whole we-have-to-get-ready thing super seriously, and as much as he appreciated his brother’s careful planning, some of it seemed almost over the top.

Two special mattress-protecting bedcovers made their way into the cart. At Hiro’s confused look, Tadashi explained, “We can use both of our beds, and I can change the sheets on the other while you’re resting.”

“Ah.”

Hiro trailed after Tadashi as they walked by other people – couples, singles, groups. Only a few bothered to spare the pair more than a second glance, but Hiro didn’t care. He knew that siblings helping siblings through heats was rare, but it definitely happened – as did siblings shopping together in an adult store, he supposed.

“A fake, vibrating knot,” Hiro noted, unimpressed as Tadashi put it in the cart. “What, you don’t think you can keep up?”

Tadashi rolled his eyes and kept browsing. “It’s not that. Remember, this isn’t going to be pleasant for me either. I’m not making any promises about whether I can ‘keep up’, and you already know that omegas tend to have a stronger libido when in heat.”

Hiro looked down. He’d only meant it as a joke, but his brother was taking everything seriously. His tone implied that Hiro should too. “Sorry.”

“Hey.” Tadashi put a hand on Hiro’s shoulder, drawing his attention. He was leaning over just a little bit, in the way that made Hiro’s heart flutter and warm up because of how reassuring Tadashi was. “I get you’re snippy because you’re nervous. But I’m nervous too. Let’s not make this any harder than it has to be.”

Hiro smiled a little bit and hugged him, grateful for Tadashi’s understanding and support. For a brief moment, while Tadashi hugged him back, Hiro sincerely wished Tadashi wasn’t his brother so they could be mate compatible.

What Hiro wouldn’t give to have an alpha like Tadashi.

BH6BH6BH6

_Hiro moans as his brother pumps his dick and bites his shoulder, trying to make the younger of the two come._

_“Just knot me already!” Hiro whines, half-delirious from the fever. It feels good, but he needs to be knotted, **now**. _

_Tadashi responds by prodding the rim of Hiro’s hole, stimulating it gently. He pushes a few fingers in, exploring the unusually relaxed orifice. Hiro whimpers and leans back into the bed a bit as he feels his inner walls be massaged. “You need to relax, babe. Come for me,” Tadashi croons, leaning back._

_Hiro is ready to cry. “I want your knot,” he whispers._

_Tadashi doesn’t answer, instead opting to thrust his fingers in and out of Hiro, making him produce more slick and loosen more._

_“Tadashi!”_

_The fingers thrust in deeper and deeper, looking for that bundle of nerves to make Hiro come. Hiro’s hands flail until they find a home in Tadashi’s hair, stubby and short._

_“Please!”_

_The hand around Hiro’s dick quickens, and Hiro whines. He can barely think through the fever, let alone the relentless stimulation from his brother. Another finger slips in, barely noticed, and finds the spot Tadashi is trying so hard to reach._

_“Ah!”_

_Hiro cants his hips back as Tadashi hits the nerves dead on repeatedly. Pleasure courses down Hiro’s legs, and before he knows it, he’s coming. Seed sprays onto Hiro’s stomach, hot and messy._

_But even after that, Hiro is still hard. It’s the heat keeping him erect, but Hiro doesn’t care. His legs pull Tadashi closer out of frustration that Tadashi isn’t in him yet._

_“I need you **in me**!” Hiro snaps right into Tadashi’s face, suddenly furious after Tadashi keeps stimulating him instead of fucking him. _

_Tadashi shushes him. “I can’t do that right now. I just knotted you an hour ago,” he says quietly._

_“No!” Hiro shouts. “Fuck me!”_

_Hiro shuts up as something hard presses into him. It’s huge, like a knot, but not as warm. Hiro moans as it pushes against his prostate. Tadashi’s hand is strangely on his ass as he pushes it in and out, whatever it is – dimly, Hiro knows that means it isn’t really his dick._

_Then it clicks and suddenly there’s a buzz on his prostate. Hiro’s hips snap up and his legs pull Tadashi closer._

_Tadashi’s hand keeps going up and down on his dick, but Hiro focuses more on and is confused by the thing in his ass. It feels good, but he only feels partly appeased._

_Hiro pushes down against Tadashi’s hand, which forces it into him, harder, and Hiro cries out as his body splits apart, coming yet again. This time, his dick flags, and Tadashi releases it gently. The buzzing stops, and the intrusion disappears._

_If it were really Tadashi’s knot, Hiro would still be hard, coming continuously with him until their lengthened orgasms died off thanks to some of the hormones emitted by a knot, and then they’d be stuck for a while. While Hiro can’t articulate the thought with all the pleasure and fever affecting him, he still knows Tadashi didn’t knot him._

_“You didn’t…” Hiro whimpers, feeling a tear slide down his face. His glazed eyes half-focus on Tadashi._

_Tadashi moves his arms to either side of Hiro’s head, caging him in with his body and holding him gently. “Sh, sh. I did what I had to do. How are you feeling?”_

_Hiro throws his head back and to the side. “I want your knot,” he whispered. Then his face contorts angrily and he starts writhing under Tadashi. “You didn’t give it to me!”_

_Tadashi smiles sadly and leans back. “Do you want me to come back in a few minutes?”_

_Hiro whips his head side to side, still feverish, as he sits up a bit to pull Tadashi down and closer, as if his outburst never happened. “I need you.”_

_Then he promptly passes out._

BH6BH6BH6

Hiro almost forgot about the other stipulation his aunt had: see a doctor. Yea, he knew it would happen for the contraceptive shots, but he’d almost forgotten.

Dr. Drake nodded at them a few times once they described the research and preparation they’d done, from the logistics of getting it on for a few days to the social pressure they might face after. He made a few notes on his clipboard and then said, “Well, it sounds like there’s not a whole lot left for me to tell you about. I can give you your shots and my phone number in case there are any problems.”

Tadashi smiled sincerely, grateful for the doctor’s back-up. “Thank you so much, Dr. Drake.”

“I’ll have one of the nurses give you your shots.” The brothers were left alone in the examination room, waiting.

“Tadashi?”

“Mm?”

“I just wanted to say thanks. For – for going through this with me.”

Tadashi smiled at him, and Hiro felt his heart warm. Before Tadashi could reply, a nurse knocked on the door.

“Come in,” Hiro said.

“Hi, boys,” the nurse said as she walked in. “Contraceptive shots, right?”

“Yep.”

BH6BH6BH6

_Hiro crawls over the bed to kiss Tadashi’s lap, having just woken from a nap._

_“Yes, it’s been – yes, and no signs of slowing down,” Tadashi says. He’s on the phone. There’s a pause, and Hiro takes that as his cue to grab onto Tadashi’s waist and lick his stomach, too. One of Tadashi’s hands rubs his back, gentle and soothing, but Hiro wants all of Tadashi’s attention._

_“Baymax, what’s Hiro’s temperature been?”_

_The robot replies, “Over the past twelve hours, Hiro has had a steady temperature of between 102.3 and 102.8 degrees Fahrenheit.”_

_Tadashi pats Hiro’s head as he relays the information. Hiro whines at the lack of full attention, mouthing over his brother’s cock. He licks at it gently, and his arms pull at Tadashi’s sides, keeping the older one from shifting away._

_“Hiro, stop that,” Tadashi says sternly before turning back to the phone. “I’m sorry, what?” Hiro whines as Tadashi refuses to turn all his attention to him. Tadashi’s cock is in his mouth as he does so, and Tadashi gently pulls Hiro’s face off of it, ignoring Hiro’s distraught sounds. “Yes, he’s awake and insistent.”_

_“Tadashi,” Hiro moans._

_“Hiro, I’m talking to Dr. Drake,” Tadashi informs him sternly, as if Hiro will make the connection that it’s important and no, Tadashi can’t let Hiro suck him off just then. He laps at Tadashi’s cock again, and this time, Tadashi pulls him further away and says, “No, Hiro. Wait.”_

_With a pout, Hiro pulls away from Tadashi and flops back on the bed, twisting to put his feet on Tadashi’s lap. For a minute, he listens. The sound of Tadashi’s voice is soothing, if it seems a bit strained or stressed._

_Boredom leers at Hiro, and Hiro thinks about the article he read with Tadashi, about how the gag reflex and pain receptors will shut down during heat – mostly what runs through his mind is that now’s the time to be giving blowjobs._

_Impatient for something sexual, Hiro reaches behind himself and shoves three fingers in without pretense. His own slick lubricates himself as the fingers pump in and out._

_Tadashi tenses when he realizes what Hiro is doing._

_“I have to go.” Hiro grins._

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“I’m still hungry,” Hiro admitted quietly. Tadashi took him out to dinner at a local pasta restaurant since Hiro was craving spaghetti. It was known for its enormous proportions and cheap prices – one meal often sufficed for three.

Tadashi smiled and offered his own plate. “It’s penne. Do you want some?”

Hiro pushed his own plate away and hesitantly nodded as he took Tadashi’s leftover pasta. He took a few bites, careful not to meet Tadashi’s eyes.

This was something mates did – taking each other out to dinner, sharing food. But Tadashi was just his brother and would never be anything more than that to him.

At that thought, Hiro stopped eating abruptly, fork halfway to his mouth. Aborting, he replaced the noodle on the plate.

“I thought you were still hungry?” Tadashi asked, showing concern. Then he seemed to realize that there was something else going on in Hiro’s mind – and as usual, he was right. “What’s going on?”

Hiro shrugged. “I’m eating as if I’m preparing for a full heat. But the whole point of this is to have a shortened one, so I shouldn’t eat as much as my body tells me to.”

Tadashi frowned, considering what Hiro said. “It would put my mind at ease if you ate to your heart’s content.”

Hiro frowned back. “But I don’t want to have leftover heat-fat. That’s just… I don’t know. I don’t want to have to work off a number of pounds.”

Tadashi smiled a little bit. “You could stand to gain some weight, you know. But really, you should listen to your body. If it wants you to put on a lot of weight for this heat, then you should. Maybe you’ll expend more energy than you think. And you know, you’re beautiful no matter what you weigh. You look great.”

Before Hiro could think of a reply, Tadashi leaned over and stabbed some penne with his own fork. He held it up and brought it close to Hiro’s face. “Choo-choo, here comes the pasta express!”

Hiro couldn’t help but smile as he batted away Tadashi’s arm. “I’m not _five_.”

Tadashi shrugged, putting the pasta in his own mouth instead. “Suit yourself.”

Hiro laughed, digging in once again.

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_“Is it gonna hurt?”_

_Tadashi shakes his head, and Hiro can feel it in his hair. He’s sitting in Tadashi’s lap on the bed, and Baymax is preparing an injection._

_“Your pain receptors aren’t working, sweetheart,” Tadashi reminds him, murmuring into his hair. “I promise it won’t hurt.”_

_Hiro turns halfway around in Tadashi’s arms. “You promise?”_

_“I promise.”_

_Hiro smiles a little and turns around again. He was just knotted a few minutes ago, and he’s relaxed, content to be held by Tadashi while his body continues to be a mini furnace._

_“Am I pregnant?” Hiro asks suddenly, for no reason at all._

_Tadashi laughs breathily. “I doubt it. We got contraceptive shots, remember?”_

_Hiro did remember. “They hurt,” he whines. “I don’t want to.”_

_Luckily, Tadashi understands Hiro even when his speech is half-formed. “This shot won’t hurt. I promised, remember?”_

_Hiro turns sideways in Tadashi’s arms, nuzzling his neck. Tadashi shifts, opting to release one of Hiro’s arms and hold the rest of him._

_Just as Hiro is about to move his arm back into Tadashi’s embrace, a foreign hand takes hold and pulls his arm away. Hiro kicks out to the side, alarmed at the stranger’s presence and the sudden acrid smell of alcohol._

_“Tadashi!”_

_“It’s okay,” Tadashi says softly. He leaves one arm around Hiro’s waist and uses the other to pull Hiro’s head under his chin, holding the side of face. The warm, secure embrace – even if it excludes his arm – is reassuring, even with the not-human stranger-thing._

_The alcoholic smell is strong and nasty, and Hiro whimpers. Whatever’s got his arm is holding it steadily and rubbing his upper arm, making it cold._

_“I will now insert the needle,” says a disembodied voice. Hiro doesn’t have time to react before he feels a prick in his arm. Tadashi’s right – it doesn’t hurt._

_“Does it hurt?” Tadashi asks. His voice is smooth like velvet and comforting._

_Hiro shakes his head, closing his eyes. “Why the shot?”_

_Tadashi just rubs his side and hums. “It’s to keep you healthy. Baymax said your blood sugars were getting too low.”_

_“Hn?”_

_Tadashi squeezes him. “You’re hungry but can’t eat, so you needed a shot.”_

_This should have alarmed Hiro – but Hiro can barely remember what “Baymax” means, let alone body activity in a normal heat. Instead, he just says, “Hnn…”_

_“Do you want to go to sleep?”_

_Hiro nods. Some part of his mind vaguely registers that he now has a band-aid on his arm where the prick was, but it doesn’t hurt and he doesn’t focus on it._

_Instead, he leans against Tadashi as Tadashi reclines, holding Hiro on top of him the entire way down. They fall asleep like that._

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This must have been the most awkward situation Hiro’d ever been in.

He and Tadashi were at the police station. The officer looked as if he were half asleep and completely uninterested in anything they had to say, so long as he was paid.

“How can I help you?”

Tadashi cleared his throat nervously, and Hiro sidled up next to him for moral support. “We’re here to file for, um, helping him through his heat.” He gestured at Hiro and extended a hand with some forms in it, filled out with precise and neat handwriting.

“I don’t think you need to file for that,” the officer said, making no move to take the papers.

Tadashi swallowed, and Hiro felt sick. This was so awkward. It seemed the officer hadn’t realized they were brothers. “We’re brothers. Incest is illegal, but this is one of the exceptions allowed, provided that participants are both over the age of 15 and provide the state with prior notice. You need to, um, file these.”

Hiro looked at the ground while the papers shuffled and fluttered their way into the officer’s hands. The silence was heavy and thick, and Hiro thought he might drown.

“I’ve never heard of this before,” the officer said eventually. “You mean you don’t have the same rank?”

Tadashi replied, “No. It’s rare.”

“Give me a minute.”

The officer let them stew for a little longer, checking something on his computer. He clicked a bit, read, clicked some more, then read more. After a few minutes, he seemed to find some kind of procedure. Hiro watched him compare the papers they’d filed out with something on his screen. A few tick marks later, and the officer paused.

“So let me get this straight,” the officer said as his eyes bore into them, his drawl judgmental and condescending. Hiro knew that not everyone would respond positively to the idea of two brothers fucking for a few days, especially since it wasn’t common. “You’re going to have sex with your little brother, repeatedly, over the course of a few days, and you need to file with the police because that’s illegal under normal circumstances?”

Hiro appreciated how Tadashi looped an arm around his shoulders, as if protecting him from the harsh tone of the officer. “Yes, sir.”

The officer nodded slowly and resumed his paper-filling. Eventually, he stopped. “I need verbal consent from both of you,” he said, his face tired and world-weary and just barely masking his disgust. “Do you both agree to this sexual conduct?”

“Yes,” said Tadashi.

Hiro nodded.

“Verbal,” the officer repeated.

“Yes,” Hiro said meekly.

The officer made one last note on the papers. “That’s it,” he said. He looked away as if he didn’t want to look at them. “You’re free to go.”

Hiro couldn’t wait to get out of there.

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_Hiro sits down on Tadashi’s lap. Tadashi is nearly asleep on the bed, on his back. They’ve knotted maybe an hour ago and are still naked. Tadashi is tired, and Hiro can see that._

_But Hiro’s also as horny as fuck and needs him to get hard._

_“Hiro, I can’t,” Tadashi says, swatting the younger’s hand aside and away from him. Ever the considerate heat-partner, Tadashi notices that Hiro isn’t ready to sleep and is ready to be knotted. “Do you want me to get you off?”_

_“Knot me,” Hiro answers._

_“I can’t,” Tadashi says tiredly. “I really can’t, Hiro. I would if I could, and I want to, but I – hey!”_

_Hiro, strengthened by his body’s crazy hormonal state, grabs both of Tadashi’s wrists, interrupting him. He yanks them up, sitting on Tadashi’s waist._

_Up until now, Hiro’s been under Tadashi. Tadashi, taking care of him; Tadashi, touching him; Tadashi, controlling everything; Tadashi, Tadashi, Tadashi. But now Tadashi’s tired, and Hiro needs to fill the gap or he won’t be able to have Tadashi’s knot._

_“Hiro? I said I – ” Tadashi’s words die in his throat as Hiro rocks his hips, grinding against Tadashi’s stomach and leaning forward until their faces are a few inches apart._

_Face flushed and eyes half-lidded, Hiro whispers, “Please.”_

_Tadashi’s breath hitches and he closes his eyes. Hiro’s bony and lithe figure presses flush against him, hot and flushed, and Hiro savors the way he can feel Tadashi’s body, hot and lithe under him. He leans down and puts his lips against Tadashi’s in a sweet kiss._

_Tadashi seems compliant enough, so Hiro lets go of one arm and reaches behind himself. Without preamble, he plunges three fingers into himself, rubbing and slickening himself for Tadashi’s knot. Tadashi doesn’t move his arm to stop Hiro, so Hiro slides down against him, pressing more of their bodies flush together while kissing him and fingering himself._

_Hiro hums into the kiss and knits his eyebrows as he fingers himself as deep as he can go._

_Fingers coated in slick, Hiro withdraws his fingers and pulls back a little bit from the kiss. He can feel that Tadashi isn’t hard under him, not yet._

_“Hiro…” Tadashi says softly._

_Hiro bats his eyes once and playfully draws up his hand covered in slick. He locks eyes with Tadashi as he licks a stripe down one finger, slowly, showing off his tongue._

_Tadashi can’t seem to look away. But he’s not protesting anymore._

_Once Hiro’s mostly done cleaning off his hand, he leans down and kisses Tadashi again. He’s certain that Tadashi can taste him from his lips – there’s no way Tadashi could miss it. Hiro lets go of Tadashi’s other hand to cup Tadashi’s face as he Frenches him, but Tadashi doesn’t move, save for how his breath hitches as Hiro grinds down into him._

_Hiro keeps his eyes closed as he explores his partner’s mouth, licking behind the teeth and slipping their tongues together. Mesmerized by every crevice, every contour, Hiro hums._

_Below him, Hiro can feel Tadashi getting hard, slowly but surely. He smiles into the kiss. He knew Tadashi had another knot in him – he just knew it. It just takes a little coaxing._

_Hiro holds Tadashi’s face as he leans back a little for air. With the smile of an imp, he scoots down and nips Tadashi’s collarbone._

_“Ah!” Tadashi’s exclamation is short, but it’s everything Hiro wants to hear. Hot hands find their way to Hiro’s sides, supporting him as he rubs their pelvises together and suckles on Tadashi’s collarbone._

_“Geez, Hiro,” Tadashi says breathlessly. His breath hitches as Hiro nibbles, grazing with his teeth._

_Hiro knows Tadashi is tired, so he takes it on himself to line up and sit down on Tadashi’s dick. Tadashi gasps, almost as if in pain, but he doesn’t push Hiro off. His hands slip down Hiro’s sides and rest on his thighs as Hiro sits back to get a better angle for himself._

_Hiro grins, eyes half-lidded, and pinches one of Tadashi’s nipples, savoring the way Tadashi’s hands clench almost tightly enough to bruise. Then he bounces, clenching his ass for Tadashi._

_Tadashi throws his head back as his breathing gets unsteady, and his hands clench and unclench as Hiro pleasures the both of them._

_Up and down, up and down – Hiro rides until his thighs feel hotter than usual, but there’s no pain as he keeps going. Tadashi even kicks in, too, hips snapping up to meet Hiro’s bounces and arms keeping him lined up._

_Hiro gasps as Tadashi decides to fondle his dick as he rides. He’s long gone before Tadashi comes with a low groan, filling him up and locking all the seed in him._

_Thought is nearly impossible for Hiro as he keens at the bulge in his ass. He’s thoughtlessly still bouncing a tiny bit, riding out both of their pleasure._

_They’re both shaking a little bit as they come down, still locked together. Hiro’s dick is limp, but there’s still a while before Tadashi’s will flag and release them._

_Hiro blinks and smiles fondly at Tadashi, who’s still reclined in the bed. His face has a fleck of Hiro’s come on it, and a large pool of it on his stomach and chest._

_Tadashi smiles back, fondly and tiredly. Without saying anything, he reaches toward the nightstand, where damp and dry washcloths wait to wipe away sweat and semen._

_With a shake of his head, Hiro stops him and stretches out himself, taking the washcloth. He haphazardly wipes off Tadashi, who places his hands back on Hiro’s thighs and massages gently._

_They remain in that position until Tadashi’s knot is gone, and Hiro pulls off to flop down on his chest. Sleep claims him in a moment, and he doesn’t register Tadashi’s fond petting._

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When people say “heat”, they usually just refer to the sexy parts – the days of marathon sex and lovey-dovey shit and mating.

They don’t usually include the weeks prior to the sex week. There’s first the put-on-weight and stock-up-energy phase where omegas eat, eat, eat, and eat. Then, about twelve hours before the heat starts, there’s the clearing of the digestive tract so the ass is empty.

That’s what Hiro was experiencing.

Hiro coughed, spitting out some more vomit into the toilet. Tadashi rubbed his lower back, gently, as if he were just sick, not emptying his digestive system to turn part of it into his reproductive system for a few days.

“Hey, buddy,” Tadashi said, once Hiro seemed to be done. Keeping one hand on Hiro’s lower back, he held out a cup of water. “How are you feeling?”

Accepting the water, Hiro rinsed and spit before flushing the toilet. Then he swallowed shallowly and leaned back from the toilet. He shook his head.

“I don’t feel hot yet,” he said, “but I do want to use the bathroom, if you don’t mind…”

Tadashi smiled a little and stepped out. Once Hiro finished, he wandered out to find Tadashi sitting on his bed, waiting for him. Baymax stood in his charger, watching them silently. Knowing that Baymax was probably logging everything he could tell about Hiro, Hiro couldn’t help but feel a touch embarrassed.

“What do you want to do?” Tadashi asked. Hiro shrugged. “We could watch a movie on your computer, play video games, design something… It’s up to you.”

Hiro nodded silently, feeling sluggish and tired. “Um… I guess a movie sounds nice.”

Tadashi smiled his ever-lovable smile, and Hiro flushed, returning a weaker smile. They traded places as Tadashi set up a movie, rearranging the monitor so that they could watch from the bed.

It was some superhero action thing, but Hiro didn’t really care. As they watched he found he couldn’t focus properly and had to ask Tadashi who the main character’s friends were. His attention was actually on Tadashi, who had an arm around his shoulders and held him against his side.

Tadashi was really hot – not temperature wise but physically, Hiro thought. He could feel the result of semi-regular gym activity through their clothes, and Tadashi’s face was handsome. Hiro unthinkingly turned his face to Tadashi’s chest, just thinking that he wanted to snuggle.

Tadashi laughed and stroked his hair with his free hand. “Are you even watching, Hiro?”

Hiro shook his head, suddenly apprehensive.

Tadashi, ever perceptive, turned his head so that they were looking at each other. “What’s going on?”

Hiro blinked, then turned away and onto his side so that there was space between them. “I just… I just want this over with.”

Somehow, Hiro could hear Tadashi’s smile in his voice. “Hey – I got this.” Hiro relaxed as he felt Tadashi roll over and spoon him from behind, sliding an arm under him so he could hold him securely. "Baymax and I will take care of you.”

It felt like there was a baseball in Hiro’s throat as he tried to swallow. “I’m scared,” he whispered.

Warm hands held his torso, and hot breath ghosted over his ear as Tadashi whispered back, “I got you.”

They stayed like that, the movie ignored by both of them, until Hiro had to throw up again.

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_Hiro wakes up to find a hand between his legs. He jerks away, only to find that there’s a body behind him._

_“You’re awake!” Tadashi says with surprise. “And you’re not hard,” he says, mystified. Hiro vaguely wonders why Tadashi would comment on that before deciding that that can wait._

_He pulls on Tadashi’s hand, and Tadashi moves it to his midriff. The smaller of the two turns around from where they’d been spooning, and looks at Tadashi straight-on._

_“Hello, Captain Obvious,” he says, nonplussed._

_Tadashi studies him for a half second, eyebrows knit. “How are you feeling?”_

_Blinking slowly, Hiro says, “Tired. Hot.” He yawns once, big._

_Despite Hiro’s calm, Tadashi scrambles to sit up and says, “Baymax, what’s Hiro’s temperature?”_

_Hiro’s surprised that Baymax doesn’t say anything before he remembers that they temporarily reprogrammed him to use the display to communicate more than his voice. Curious, Hiro too sits up, eying Baymax’s bright stomach._

_It’s displaying a graph, one that is fairly level and then starts curving down halfway through._

_Hiro grins and turns to Tadashi. “Looks like my heat’s almost over.” Sidling up to Tadashi, he hugs him close, ignoring their nakedness. It’s not like Tadashi hasn’t seen any of it before. “Thank you.”_

_Warm arms encircle him, snug and secure. “You’re welcome. Baymax, could you go downstairs and tell Aunt Cass Hiro’s almost done?” They settle into the bed again, wrapped around each other as Baymax toddles down the stairs._

_A few minutes later, Hiro laughs. “You know, I’d’ve thought that having sex with me would make you want to put some distance between us for a bit. Or that I’d want some.”_

_“Do you?”_

_Hiro shakes his head, knowing Tadashi could feel it under his chin. The elder’s arms circle him and pull him closer; Hiro melts into the hold, perfectly content._

_Tadashi decides that explanations can wait._

**Author's Note:**

> Eheheheh Hiro WAS SO OUT OF IT HE DIDN'T CATCH IMPORTANT CLUES MUHAHAHAHA ~~~ Aftermath next chappie :-) 
> 
> Anyway, I hope you liked this!! Leave kudos, I appreciate them lots. :-)


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